Description:
"There was Eru, the One, who in Arda is called Ilúvatar; and he made first the Ainur, the Holy Ones, that were the offspring of his thought, and they were with him before aught else was made."

"Thus it came to pass that of the Ainur some abode still with Ilúvatar beyond the confines of the World; but others, and among them many of the greatest and most fair, took the leave of Ilúvatar and descended into it. But this condition Ilúvatar made, or it is the necessity of their love, that their power should thenceforward be contained and bounded in the World, to be within it for ever, until it is complete, so that they are its life and it is theirs. And therefore they are named the Valar, the Power of the World."

The Silmarillion, Ainulindalë, The Music of the Ainur

Valar (plural), Vala (singular)

Lords of the ValarManwë - Lord of the Breath of Arda (first of all Kings, lord of the realm of Arda), surnamed Súlimo; spouse to VardaUlmo - Lord of the Waters, King of the SeaAulë - who has lordship over all the substances of which Arda is made; spouse to YavannaOromë - Lord of the Forests, also called Aldaron or Tauron; spouse to Vána; sibiling to NessaMandos - true name is Námo, Keeper of the Houses of the Dead, the Doomsman of the Valar; spouse to Vairë; sibling to Irmo (Lórien) and NiennaLórien - true name is Irmo, the master of visions and dreams; spouse to Estë; sibling to Námo (Mandos) and NiennaTulkas - the Valiant, surnamed Astaldo; spouse to Nessa

Queens of the ValarVarda - Lady of the Stars, also called Elbereth (Star-Queen), who among the Valar is the one most beloved by the Elves; spouse to ManwëYavanna - Giver of Fruits, surnamed Kementári (Queen of the Earth); spouse to Aulë; sibling to VánaNienna - "all those in Mandos cry to her, for she brings strength to the spirit and turns sorrow to wisdom"; sister of the Fëanturi (Námo and Irmo)Estë - the gentle, healer of hurts and wearinessVairë - the Weaver, who weaves all things that have ever been in Time into her storied webs; spouse to Námo (Mandos)Vána - the Ever-Young, "All flowers spring as she passes and open if she glances upon them; and all birds sing at her coming."; spouse to Oromë; sibling to YavannaNessa - lithe and fleetfooted; spouse to Tulkas

The Silmarillion, Valaquenta

(Note: In The Shaping of Middle-earth, there are Nine Valar, with differing "family" relationships.)